I don't think they host them on a regular basis. From what I've gathered, it's a case of someone going to the cruise director at the beginning of the cruise and suggesting it - if he gets more than one or two requests ( & is "friendly") he may make an effort to include it, but I wouldn't expect it - talk to your cruise director directly & be up front. We ARE everywhere! Hell, I live in Northern Greenland and there's 5-6 known to me here out of 600 - we have the best time possible ( and we're going en masse to the Feb 11-18 RSVP cruise).
Carnival Victory 15-22 Oct 2000
QE2 22-27 Oct 2000
Ocean Princess 29 Oct - 5 Nov
Ocean Princess 5-12 Nov...
Betty Ford 13 Nov - 31 Dec 2000 ;-)